This invention comprises an interface device for the entry of data into an instrument of small volume such as a timepiece comprising a static touch responsive sensor arranged to be manually actuable with each position of a finger corresponding to at least one symbol which may take the form of a number, letter or special sign, the sensor being formed by the juxtaposition of N electrodes adapted to provide at least N-1 coded information items representative of the position of the finger on the sensor.
The invention relates to U.S. patent application No. 968,917 filed 13th December 1978 and allowed May 1980, and which concerns an interface device for data entry for small volume instruments and for which it comprises a particularly interesting improvement above all in view of its application to timepieces. The above cited application starts with the idea of a data entry device capable of being manually actuated and furnishing information representative of the position of a finger on a sensor, (resistive or capacitive), such information being independent of the width of the finger. To arrive at such a result use has been made of a sensor formed by the juxtaposition of a plurality of identical electrodes providing at their output information according to a binary code representing the position of the finger on the sensor.
The cited system may already provide an important improvement in the case where it is employed for the correction of a timepiece having an electro-optic display. Taking as an example a situation where the timepiece includes in addition to the main display of the normal timekeeping operation which appears permanently, a secondary display which may sequentially display a count-down timer, an alarm timer, a diary, a time zone, a date, etc.. All these several functional modes may be indicated by permanent signs engraved or transfered onto the interior surface of the glass. The touch sensitive key described in the above cited application may initially be employed to select the functional mode or programme. By moving the finger on said key a symbol is also moved which for instance may frame one of the permanently fixed signs and thus one may select the programme chosen when the finger is removed from the key. Should one then actuate a pushbutton the display corresponding to the programme as chosen will be transfered into the correction mode, this being indicated by blinking of the display. The correction may again be made by the touch sensitive key. If the display chosen includes a digit or a group of two digits for instance such may be augmented by moving from left to right the finger over the sensor, or diminished by the same movement but from right to left. If the number to be corrected is that of the minutes of a main display for instance, it will be appreciated that relative to known systems of correction by means of a pushbutton the cited device may enable attainment much more rapidly of the required correction, in the case where the timepiece has advanced several minutes since it will be sufficient to move the finger from right to left over a short distance in order to diminish the number and thus to bring it to the value of the timing signal.
The time indications displayed by a timepiece generally include not one but rather two groups of associated digits. The principal display of normal time of day comprises at least the indication of minutes and hours. On the auxiliary display there may appear an alarm time or a time zone of which the first digit group may indicate the hour and the second group the minute. Also there may appear on this display a diary for which the first group may indicate the month and the second the date. In a different mode or programme the same basis is provided for display of the day of the week and of the date which may appear simultaneously. If the watch is provided with a count-down timer, the latter may indicate a lapse of time comprising associated indications of hours and minutes which it must count-down. For each of the timing indications mentioned above it is necessary to foresee two correction modes, the first acting for instance on the group of numbers or digits to the left and the second on the group to the right. In known watches the changing of a correction mode from one timing to another and from one group to the other for each timing indication is accomplished by means of a pushbutton as has been mentioned in the preceding paragraph, this requiring thus a multiplicity of actuations of the pushbutton and thereby a succession of tedious operations.
The present invention proposes to overcome the above mentioned difficulties through correcting as a group each timing indication and the digit groups of which it is composed without the necessity of changing the correction mode for each of the groups one after the other. It takes advantage of the fact that the finger may be displaced at different speeds on the sensor and that means may be employed in order that by slow motion one group may be corrected and that through a rapid motion another group may be corrected.
The device of this invention and the means employed for the realisation thereof are defined in the claims hereto attached.